To date, polyurethane is one of the best performing products. It allows you to attain a high R-value in a narrow spacing. It also acts as an air and vapour barrier. As regards thermal roofs, polyisocyanurate panels are among the most efficient on the market.
type de question: Insulation
How to calculate the R-value of the insulation?
The insulation requirements vary depending on the building system. It is suggested to consult the description sheet to know the R-value of the insulation. The data may vary in case of a rooftop terrace or green roof.